Abstract: An intake air amount control system for an internal combustion engine installed in an automotive vehicle has an intake air amount control valve arranged in a bypass passage bypassing a throttle valve arranged in an intake passage of the engine. The intake air amount control valve controls the amount of air supplied to the intake passage at a location downstream of the throttle valve. The intake air amount control valve is controlled in dependence on operatives states of electric devices including an electrically-heated catalyzer which are installed on the vehicle and supplied with electric power by an alternator installed on the vehicle and driven by the engine, when the engine is in a predetermined operating condition. The intake air amount control valve is controlled by the use of a correction amount dependent on an operative state of the electrically-heated catalyzer.

Abstract: An electrical load abnormality-detecting system for an automotive vehicle detects abnormality of each of a plurality of electrical load devices installed on the vehicle. A current sensor is provided commonly for the plurality of electrical load devices, for detecting a total load current flowing through the plurality of electrical load devices. The plurality of electrical load devices are separately put into operation, and abnormality of each of the plurality of electrical load devices is determined based on the total load current detected by the current sensor.

Abstract: A control device is provided for controlling an electrically-heated catalyzer of an internal combustion engine. Electric power generated by an alternator driven by the engine is supplied to the electrically-heated catalyzer. At least one electrical parameter dependent on the electric power supplied to the electrically-heated catalyzer is detected. It is determined that the electrically-heated catalyzer is abnormal when the at least one electrical parameter falls outside a predetermined range. The predetermined range is changed according to the rotational speed of the engine detected by an engine rotational speed sensor.

Abstract: A control system controls an alternator driven by an internal combustion engine, for generating electric power. A changeover switch selectively switches the destination of electric power generated by the alternator to a plurality of electric load groups having respective different load voltage values, each electric load group having at least one electric load. An ECU controls switching operation of the changeover switch and changes output voltage from the alternator between a plurality of different predetermined voltage values corresponding, respectively, to the plurality of electric load groups, according to a direction in which the changeover switch has been switched.

Abstract: An exhaust gas-purifying system is provided for an internal combustion engine for use in a vehicle having an alternator driven by the engine to generate electric power. An electrically-heated catalyzer is arranged in the exhaust system of the engine and connected to the alternator to be electrically heated thereby. A changeover switch is provided for selectively switching the destination of electric power generated by the alternator to the electrically-heated catalyzer and to the electrical equipment. An ECU controls the electric power generated by the alternator, depending upon a direction in which the changeover switch has been switched. The ECU detects abnormality of the changeover switch, and when the abnormality is detected, the electric power generated by the alternator is changed to a value smaller than a value assumed when the changeover switch is normal.

Abstract: An exhaust gas-purifying system for an internal combustion engine includes an alternator driven by the engine. A regulator controls voltage generated by the alternator. An electrically-heated catalyzer is arranged in the exhaust system of the engine and connected to the alternator to be electrically heated by electric power generated by the alternator. An ECU controls the regulator to control the voltage generated by the alternator and supplied to the electrically-heated catalyzer, according to operating conditions of the engine detected by sensors such as an engine coolant temperature sensor and an intake air temperature sensor.

Abstract: A system for controlling an idle speed of an internal combustion engine having an electrically heated catalytic converter which is heated up when current is supplied from an alternator driven by the engine. In the engine idle control, a basic value of a desired idle engine speed is determined with respect to the engine coolant temperature in the same manner as the prior art. However, an augmentative correction amount of the desired idle engine speed is determined with respect to the exhaust system ambient temperature. More specifically, the desired idle engine speed is increased in response to the heating of the catalytic converter so as to prevent the alternator from generating electric power insufficient for heating up the catalytic converter.

Abstract: A system and method for detecting a failure occurring in an exhaust secondary air supply system of an internal combustion engine. A conduit is connected to the exhaust pipe to supply secondary air to the exhaust pipe to promote oxidization of the emissions in the exhaust gases. A valve is provided in the conduit for opening/closing it. The failure of the valve is detected by operating the air pump to supply the air in the conduit, while closing the conduit by the valve. The air/fuel ratio is detected by an oxygen sensor installed downstream of the conduit to be compared with a desired air/fuel ratio. If the detected air/fuel ratio is leaner than a desired air/fuel ratio, the air flows to the exhaust pipe so that the valve is considered to be stuck to open. Alternatively, a pump current is detected and is compared with a reference value indicative of the current at no air flow. If the detected current is less than the reference value, the valve is considered to be in failure.

Abstract: A system for detecting a failure of an electrically heated catalytic converter installed in an exhaust system of the engine for reducing pollutants from exhaust gases emitted from the engine, the catalytic converter having a heater which is connected with the power source to be supplied with current. A parameter such as electric power consumption indicative of an electric resistance of the heater of the catalytic converter. If the parameter is out of a range defined by reference values, it is determined hat a failure has occurred in the heater of the catalytic converter. In the system, reference values at a specific condition based on a correction coefficient obtained on the ratio between the parameter designed before manufacturing and that measured after manufacturing.

Abstract: A system for detecting the ambient temperature of an exhaust system of an internal combustion engine, where an oxygen sensor (O.sub.2 sensor) is installed for detecting oxygen content in exhaust gases generated by the engine. The oxygen sensor has a detection element and a heater for heating the detection element when supplied with current. The exhaust system is further provided with a catalytic converter which similarly has a heater for heating the catalyst for promoting the activation thereof. The electric resistance of the sensor heater is detected and based on the detected resistance, the ambient temperature of the exhaust system is detected or estimated in accordance with characteristics preestablished with respect to the electric resistance of the heater. With the arrangement, it becomes possible to detect the ambient temperature of the exhaust system without using a temperature sensor. The detected ambient temperature is used for controlling the current supply to the heater of the catalytic converter.

Abstract: A current control system of an electrically heated catalytic converter installed in the exhaust system of an internal combustion engine. In the engine, fuel metering is controlled by correcting a basic quantity of fuel injection by correction factors. The correction factors are grouped into the factors for increasing the fuel injection quantity at engine warmup and other factors. Therefore, the total value of the factors for increasing the fuel injection quantity at engine warmup are compared with a predetermined value, and if the total value exceeds the predetermined value, the current supply to the heater is inhibited. Alternatively, the cranking time is compared with a predetermined value and if it exceeds the predetermined value, the current supply is inhibited. Since the quantity of fuel injection is increased in these situations, unburned emissions will accordingly be increase.

Abstract: An exhaust gas-purifying system for an internal combustion engine includes an alternator driven by the engine. A regulator controls voltage generated by the alternator. An electrically-heated catalyzer is arranged in the exhaust system of the engine and connected to the alternator to be electrically heated by electric power generated by the alternator. An ECU controls the regulator to control the voltage generated by the alternator and supplied to the electrically-heated catalyzer, according to a degree of aging of the electrically-heated catalyzer.